The invention concerns a device, in particular a pump, for the conversion of a unidirectional rotational motion into a reciprocating back and forth motion.
A particularly well-known device for such operations is an eccentric disc, whose cam sits in an elongated slot in a laterally displaceable guided part. The laterally guided element moves back and forth with reciprocating motion reflecting a sinusoidal contour as a result of the rotation of the eccentric disc.
Devices are known from DE-A-3 811 820 and EP-A-0 768 408 in which an offset element is used These devices have axes which intersect at a point in space for kinematic reasons. For structural reasons when using an offset element, this point of intersection cannot lie within the area of the a offset element. Consequently a relatively large structure results, which is disadvantageous for many applications. The known devices are suited for converting rapid rotational motion stabilised by a flywheel into relatively small reciprocating back and forth motion. However, the known systems are unsuitable particularly when strong lift accompanied by a relatively small rotational motion with relatively large moment is to be produced.
The invention thus has the object of presenting a new device of the above mentioned type which, above all, requires only limited height.
This object is solved with a device according to a type which possesses the following: a disc which can be rotated about a central axis, a wobble pin which is mounted in the disc so that it can rotate around an axis which is arranged at an angle in relation to the plane of said disc, a swivel pin which is secured to the wobble pin at an angle in relation to the axis thereof, and a fastening device which prevents the swivel pin from rotating around the axis of the disc.
A particularly simple arrangement, especially for the use of the device as a pump, has the movement of the pressures plate guided by a diaphragm. The diaphragm permits movement of the pressure plate in a specified range and can at the same time serve as a seal for a pressure plate functioning as a piston.
An advantageous arrangement of the invention provides for the diaphragm to be fixed to the casing. In this way, firstly, the space of the moving components is sealed and, secondly, the diaphragm is fixed in a simple manner.
It is advantageous if the diaphragm forms the boundary of a pump chamber with a part of the casing. This permits a compact design of a device built as a pump, in which the pump together with its drive and transfer mechanism, has extremely limited height.
A preferred use of the device is when it is used to pump blood. Due to the reduced height of the device, not only can it be comfortably worn on the body, but it is also suitable for implantation in the thorax as a result of its reduced height.
The described device is particularly suitable for implantable pulsating heart support systems which can also be introduced into children and small adults. The device can either be implanted or used extracorporeally.
The device is also suitable in general for the conversion of a circular rotation into a perpendicular oscillating rotation with angle xc3x8 and is particularly suitable for the unfolding or technical structures such as, for example, brake flaps on aeroplane wings, landing gear made of thin walled structures etc.
A further advantage of the device of the invention is in the self-limiting angle setting of technical structures, thus favouring its use, for example, in limbs of robots, back rests of seats, truck rear mirrors, metal leads in distribution systems, air vents, ship rudder systems and so on. In these cases the device maintains its preset position in the event of a power interruption.
With small values of set angle ranges "psgr", very high power reduction ratios are possible if required, and the device can be operated manually or remotely using notched belts, V belts or linkages.